Do Physical Activity Levels Predict Cognitive Status in Parkinson Disease?

Cropped shot of a senior man with a walking stick being comforted by nurse in the hospice.Care worker helping to elderly patients to walk in geriatric clinic.
Researchers sought to examine whether physical activity levels predicted future PD mild cognitive impairment and PD dementia among patients newly diagnosed with PD.

Individuals with Parkinson disease (PD) who become less active are more likely to develop PD mild cognitive impairment or PD dementia, according to study findings published in Mental Health and Physical Activity.

Patients with PD often have cognitive impairment, which may include PD mild cognitive impairment or PD dementia. Among many contributors to cognitive impairment in these patients may lie decreased engagement in exercise. Patients with PD are less physically active compared with healthy older adults, and they become less physically active with disease progression, missing the benefits of exercise.

Prior studies have indicated patients with PD may have better cognitive outcomes, but the results are inconsistent and have small effects. The objective of the current study was to determine the relationship between engagement in everyday physical activity and clinical cognitive outcomes among patients newly diagnosed with PD.

Researchers examined data of 301 individuals included in the Parkinson’s Progression Markers Initiative (PPMI) longitudinal cohort study. The individuals were followed up to 3 years. Annually, they were assessed as cognitive normal or having PD mild cognitive impairment or PD dementia and self-reported physical activity.

Through ordinal multilevel models, the researchers found significant within-person and between-person effect for physical activity. Individuals who became less physically active were at increased risk for PD mild cognitive impairment and PD dementia compared with individuals who became more physically active. Individuals who tended to be more physically active had lower risk for PD mild cognitive impairment and PD dementia throughout the study. Increased risk for PD mild cognitive impairment and PD dementia was linked with more severe motor symptoms.

The researchers found that individuals who reported less involvement in physically demanding household activities and those who reported longitudinal reductions in leisure/ leisure/recreational physical activities were more likely to develop PD mild cognitive impairment or PD dementia. Cognitive impairment was linked with more severe motor symptoms.

According to the researchers, interventions used to maintain patients’ level of physical activity despite worsening motor symptoms while understanding patients’ challenges, may improve cognitive outcomes and be more effective.

“Overall, findings provide support for the clinical importance of physical activity among individuals with PD. Engagement in everyday physically demanding activities, such as exercise, sports, or other leisure/recreational physical activities, may reduce the risk of PD [mild cognitive impairment] and PD [dementia],” the researchers concluded.

Study limitations included subjective analysis of physical fitness, self-report from individuals with cognitive impairment, less comprehensive cognitive battery, limited generalizability to other populations, and limited in determining causality and directionality.

Reference

Jones JD, Baxter F, Timblin H, et al. Physical inactivity is associated with Parkinson’s disease mild cognitive impairment and dementia. Mental Health Physical Activity. Published online June 23, 2022. doi:10.1016/j.mhpa.2022.100461